Webs used in the manufacture of filter cigarettes include a web for wrapping paper used for wrapping shredded tobacco or filter materials, a web for tip paper used for connecting a cigarette to a filter, and so on. Although each of these webs is drawn from a web roll toward a cigarette-manufacturing machine or a filter cigarette-manufacturing machine, there is a limit to the length of web forming the web roll.
Therefore, in order to enable the continuous operation of the above-mentioned manufacturing machine, the manufacturing machine is provided with an automatic splicing device of webs. This automatic splicing device allows a web to be drawn from a standby web roll, not from an active web roll, when a web-remaining amount of the active web roll reaches the prescribed amount or less. Specifically, the automatic splicing device splices the first web being drawn from the active web roll and the second web of the standby web roll by using a splicing tape, and cuts the first web upstream from the splicing tape immediately after the splicing. Accordingly, the manufacturing machine is then supplied with the web from the standby web roll, not from the active web roll, and thus the standby web roll becomes an active one.
The aforementioned automatic splicing device generally splices the first and second webs together by using the splicing tape while the delivery of both the first and second webs is halted. An automatic splicing device of this type, however, requires a reservoir for the first web. The reservoir is located in between the manufacturing machine and the automatic splicing device. In advance of operation of the automatic splicing device, the first web is drawn at a higher speed than a consumption speed in the manufacturing machine side, thus being stored in the reservoir by a given length. As a result, the manufacturing machine can consume the web stored in the reservoir during the operation of the automatic splicing device, which enables the continuous operation of the manufacturing machine.
The use of the reservoir causes all sorts of problems to the web, including the entanglement of webs in the reservoir, a breakage created in side edges of the web, a fracture in the web, etc. The faster the operation speed of the manufacturing machine, or the delivery speed of the first web, becomes, the more often these problems arise.
To avoid the above-listed problems, the development of an automatic splicing device requiring no reservoir has advanced. With such an automatic splicing device, the second web is drawn at the same speed as the delivery speed of the first web and passes a splicing area adjacent to the first web. In this state, when the first and second webs overlap each other with a double-faced splicing tape therebetween, the double-faced splicing tape splices the first and second webs together. Immediately after the splicing, the first web is cut upstream from the double-sided splicing tape, whereas the second web is cut downstream therefrom.
In order to splice the first and second webs together by the above-described splicing manner, when the double-faced splicing tape is fed to the splicing area between the first and second webs, the splicing tape must be kept in a stable state while the first and second webs are delivered. If the double-faced splicing tape flaps in a large way because of the air flow created by the travel of the first and second webs, the double-faced splicing tape may adhere to either web before the first and second webs are overlapped each other, which precludes the splicing of the first and second webs.
The flapping of the double-faced splicing tape could be prevented by diminishing the flexibility of the double-faced splicing tape. Although such a hard double-faced splicing tape is effective for the aforementioned splicing manner, it also lowers the flexibility of webs themselves on a large scale.
In the case that the web is wrapping paper used in a cigarette-manufacturing machine, shredded tobacco is wrapped in the web to be formed into a tobacco rod. The tobacco rod has a seam, which is formed by overlapping both side edges of the web with an adhesive therebetween.
In this case, when the slicing portion of the first and second webs with the double-faced splicing tape therebetween is fed to the cigarette-manufacturing machine, the slicing portion of the first and second webs wraps the shredded tobacco with the bending of the double-faced splicing tape. When a restoring force of the double-faced splicing tape, that acts against the bending thereof, overcomes an adhesive force of the seam of the tobacco rod, the seam comes loose, thereby preventing the continuous forming of the tobacco rod in the cigarette-manufacturing machine.